Examples for 8th grade - page 3

  1. Above 100%
    dummy What is 155% of 210?
  2. Guests
    hostia How many ways can 7 guests sit down on 9 seats standing in a row?
  3. Stock market
    money_1 Simon one day decided to invest € 88000 to the stock market. After six months he invested July 5 stock markets fell by 56%. Fortunately for Simon from July 5 5 to October 5 his shares have risen by 39%. Simon is then: ?
  4. Height
    thales_law Is right that in any right triangle height is less or equal half of the hypotenuse?
  5. Logs
    gulatina Trunk diameter is 72 cm. Is it possible to inscribe a square prism with side 54 cm?
  6. Series
    posloupnost_an Andrew wrote this series of numbers: 1,3,7,15, .... n. Which number in the series does not belong? ?
  7. Playing cards
    playing_cards How many possible ways are to shuffle 7 playing cards?
  8. Ace
    ace From complete sets of playing cards (32 cards) we pulled out one card. What is the probability of pulling the ace?
  9. Shelf
    bookshelf.JPG How many ways are there to arrange 9 books on a shelf?
  10. Logic
    blue-barrel A man drinks a barrel of water for 31 days, woman for 58 days, for how many days they drink barrel together?
  11. Percent calculation
    percent_sign Calculate 72% if 96% is 93.
  12. Trapezoid
    rectangular_trapezoid Are diagonals in a rectangular trapezoid perpendicular and bisect the angles?
  13. Road
    cesta Between cities A and B is route 3 km long of rise average 4‰. Calculate the height difference of cities A and B.
  14. Painter Pavel
    pixla_s_farbou Painter Pavel painted the fence for 20 hours and painter Petr the same fence painted for 17 h. How long should take painted the fence together?
  15. Right Δ
    ruler Right triangle has length of one leg 7 cm and length of the hypotenuse 25 cm. Calculate the height of the triangle.
  16. KLMN
    trapezium In the trapezoid KLMN is given this informations: 1. segments KL and MN are parallel 2. segments KL and KM has same length 3. segments KN, NM and ML has same length. Determine the size of the angle KMN.
  17. Center traverse
    trianles It is true that the middle traverse bisects the triangle?
  18. Cylinder - h
    cylinder_2 Cylinder volume is 129 cm3. Base radius is 3 cm. Calculate the height of the cylinder.
  19. Beer
    piva After three 10° beers consumed in a short time there are 7.4 g of alcohol in 5 kg adult human blood. How much is it per mille?
  20. Christmas Day
    stedryd In leap years was 53 Sundays. On what day of the week fell to Christmas Day?

Do you have interesting mathematical example that you can't solve it? Enter it and we can try to solve it.

To this e-mail address we will reply solution; solved examples are also published here. Please enter e-mail correctly and check whether you don't have a full mailbox.